Copolymer compositions derived from unsaturated triazines

ABSTRACT

New compositions, useful as viscosity additives, having dispersing properties in various hydrocarbon oils, are disclosed, which comprise: 
     recurrent units derived from one or more acrylic or methacrylic esters (e.g. 55-99.8% by weight), 
     recurrent units derived from one or more nitrogenous vinyl monomers obtained by reacting triallylcyanurate with aliphatic amines or polyamines (e.g. 0.2-10% by weight), and optionally 
     recurrent units derived from one or more vinyl aromatic monomers (e.g. 0-35% by weight). 
     These copolymer compositions generally have a weight average molecular weight from 30,000 to 800,000 and a polydispersity generally lower than 5. They can be prepared by any radical copolymerization process using for example azoic or peroxydic initiators. 
     The copolymer compositions considered are used as additives for improving the rheological properties of hydrocarbon oils. in addition, they exhibit good dispersing properties.

This invention concerns copolymer compositions particularly useful asadditives for improving the rheological behavior of hydrocarbon oils(viscosity, pour point) and having dispersing properties.

BACKGROUND OF THE INVENTION

It is known to incorporate with conventional flow additives forhydrocarbon oils compounds which impart to them dispersing properties.

The different categories of so-called viscosity additives, particularlyused in motor oil compositions (for improving the thickening power, theselectivity, the freezing point, the shearing strength, etc. . . ) aredisclosed in detail, for example, by J. BRIANT and coll. in the work"Proprietes rheologiques des lubrifiants" Editions TECHNIP, Paris.

The incorporation by copolymerisation, grafting, esterification ormaleinization, of radicals carrying groups generally of the nitrogenousor oxygenated type, give dispersing properties to these additives.Accordingly, the dispersing additive amount required in the lubricatingoil composition may be substantially reduced. The most currently usedmonomers for copolymerization or grafting are 4-vinyl pyridine, N-vinylpyrrolidone and N-vinyl imidazole. The different compounds used toimpart dispersing properties to viscosity additives are moreexhaustively listed in the above-mentioned work.

The product obtained by reaction of one or morepolyisobutene-succinimides with triazine trichloride (U.S. Pat. No. 4116 875) is also known as dispersing additive.

Finally, it is known to prepare compounds of high nitrogen content,which may be used for stabilizing polyolefins by protecting them againsthot oxidation ("Synthesis" pages 182-185, March 1975), by aminolysis oftriallylcyanurate with primary amines.

SUMMARY OF THE INVENTION

Now, new copolymer compounds have been discovered which offer veryadvantageous properties as additives in various hydrocarbon oils, aswell by their action on the rheological properties of the oil and bytheir dispersing effect.

The copolymer compositions of the invention may be generally defined bythe fact that they comprise recurrent units derived from one or moreacrylic esters, from one or more monomers obtained by reaction ofaliphatic amines or polyamines with triallylcyanurate, and optionallyfrom one or more vinylaromatic monomers.

More particularly, the copolymer compositions of the invention, whichmay be prepared by radical copolymerization, contain 0-35% by weight ofone or more vinylaromatic monomers, 55-99.8% by weight of one or moremonomers of linear or branched alkyl acrylate or methacrylate type,comprising 1-22 carbon atoms, and from 0.2 to 10% by weight of one ormore nitrogenous vinyl monomers derived from triallylcyanurate. Theproportion of nitrogenous vinyl monomer is advantageously from 0.5 to 4%by weight, the proportions of the other monomers being correspondinglyadjusted.

Nitrogenous vinyl monomers, the use of which in the preparation of thepolymers according to the invention is the main characteristic thereof,are prepared more particularly by reacting triallylcyanurate with one ormore amines or polyamines complying with the general formula: ##STR1##wherein R¹ is a hydrogen atom or a linear or branched alkyl radical of1-24 carbon atoms (--C_(n) H_(2n+1)), x ranges from 1 to 10 or may be 0when n is at least 4, R², defined when x is not zero, represents thehydrogen atom or a linear or branched alkyl radical of 1-24 carbon atoms(--C_(m) H_(2m+1)), and A, also defined when x is not zero, representsan alkylene radical, for example of 2-6 carbon atoms, more particularlythe ethylene, propylene or isopropylene radical.

Examples of amines to be used are:

monoprimary monoamines of formula R¹ NH₂, such for example asn-butyl-amine, sec-butylamine, tert-butylamine, n-pentylamine, 4, 3 or 2methyl-n-butylamine, n-hexylamine, n-heptylamine, n-octylamine,n-nonylamine, eicosylamine and docosylamine; as well as their isomers:

monoprimary polyamines of formula ##STR2## such for example as N,N-dimethyl ethylenediamine, N-oleyl propane diamine, N, N-dimethyldiamino-propane, N, N-diethyl diamino-propane, N, N dimethyldiamino-isopropane, etc.; and

biprimary polyamines of formula ##STR3## such for example as ethylenediamine, propylene diamine, diethylene triamine, dipropylene triamine,triethylene tetramine, tripropylene tetramine, tetraethylene pentamine,tetrapropylene pentamine, etc.

In the triallylcyanurate aminolysis reaction, the monoprimary orbiprimary amines may be used, for example, in proportions from about 1to 2 moles per mole of triallylcyanurate.

The reaction with 1 mole of amine may conform with the following scheme:##STR4##

Optionally the reaction may be repeated with at least one part ofproduct (I), according to the following scheme: ##STR5##

Moreover, for biprimary amines, the amine proportion may be, forexample, about 0.5 mole per mole of triallylcyanurate and the reactionmay comply with the following scheme: ##STR6##

It may still be considered to react the so-obtained product with amonoprimary or biprimary amine ##STR7## in a proporton of 1, 2 or 3moles per mole of product (III) as above-defined (i.e. about 0.5, 1 or1.5 moles per mole of initial triallylcyanurate).

The conditions of the triallylcyanurate aminolysis reaction are known.They have been disclosed in particular by H. AHNE and coll. in"Synthesis", March 1975, pages 182-185, the reactant proportions beingadjusted according to the desired stoichiometry. Thus, the aminocompound (monoprimary and/or biprimary) is used in such a proportionthat, as a whole, at least one allyl double bond per molecule remains ineach product obtained. Otherwise stated, the products comprising onetriazine ring may be mono-or di-substituted and each of the productscomprising two triazine rings may have two mono- or di-substitutedrings, or even at most one of the two rings may be tri-substituted. Infact, the aminolysis of triallylcyanurate gives products having varioussubstitution degrees which are difficult to separate. They may howeverbe used as such in copolymerization, after removal by distillation ofthe allyl alcohol formed.

The acrylic ester involved in the formation of the copolymercompositions of the invention, consists more particularly of a linear orbranched alkyl portion acrylate or methacrylate containing 1-22 carbonatoms in the alkyl, alkyl methacrylates being preferred.

The acrylic esters may be used alone or as mixtures. Thus, it isadvantageous to use at least one relatively light alkyl methacrylate(e.g. whose alkyl group has 1-4 carbon atoms) and at least onerelatively heavier alkyl methacrylate (e.g. whose linear alkyl group has8-22 carbon atoms). More particularly, all the alkyl methacrylates mayinclude about 5-25% by weight of at least one linear or branched C₁ -C₄alkyl methacrylate, about 10-80% by weight of at least one linear C₈-C₁₄ alkyl methacrylate and about 15-75% by weight of at least onelinear C₁₆ -C₂₂ alkyl methacrylate. The percentages by weight areindicated in proportion to the total amount of methacrylates.

The vinylaromatic monomer optionally involved may consist for example ofstyrene, α-methyl styrene or vinyltoluene, styrene being preferred.

The copolymer compositions of the invention may be prepared by radicalcopolymerization from monomers in suitable proportions.

The copolymerization is initiated by a conventional radical initiatorsuch as those currently used in this type of polymerization (azoic orperoxidic compound).

The co-polymerization temperature ranges from 80 to 130° C., the solventbeing for example a mineral oil (100 or 200 N) used in an amount of20-50% by weight in proportion to the reaction medium, taken as a whole.

The weight average molecular weight of the products according to theinvention may range for example from 30,000 to 800,000 (as determined bychromatography by gel permeation calibrated with methylpolymethacrylate). Their polydispersity is generally lower than 5.

The copolymer compositions according to the invention are used asviscosity additives for lubricating, mineral or synthetic oils. They aregenerally added in amounts ranging from 0.5 to 10% by weight inproportion to the lubricating oil.

EXAMPLES

The following examples are given to illustrate the invention and mustnot be considered as limiting the scope thereof.

Examples 19 to 24 are given for comparison purpose. Examples 1 to 8describe the preparation of nitrogenous monomers derived fromtriallylcyanurate, used in the preparation of the copolymers accordingto the invention.

EXAMPLES 1 to 8 (Preparation of nitrogenous monomers)

10 g (40 millimoles) of triallylcyanurate (TAC) are reacted with theamine indicated in Table 1 hereinafter, in the reported molar amount.The reactions are conducted in the absence of solvent at a temperatureranging from 40°to 70° C., for about 30 hours.

For each of the products obtained, the substitution degree oftriallylcyanurate has been determined from the amount of allyl alcoholrecovered by vacuum distillation at the end of the reaction. As shown intable 1, the selected molar proportions being taken into account, thisaverage substitution degree may be close to 1 (products of example 1 and3 with 2 triallylcyanurate rings linked by substantially one biprimaryamine molecule) or close to 2 (products having one triallylcyanuratering substituted with about 2 molecules of monoprimary amine --examples5 to 8-- or with about 2 molecules of biprimary amine --examples 2 and4).

                                      TABLE 1                                     __________________________________________________________________________    Amino Compound                                                                example                                                                            (H.sub.2 N--A--NR.sup.2).sub.x R.sup.1 (*)                                                       amount                                                                            substitution degree                               N.sub.o                                                                            x n  m  --A--      mmol                                                                              of TAC                                            __________________________________________________________________________    1    4 0  0  --CH.sub.2 --CH.sub.2 --                                                                 20  1.05                                              2    4 0  0  --CH.sub.2 --CH.sub.2 --                                                                 80  1.95                                              3    3 0  0  --CH.sub.2 --CH.sub.2 --                                                                 20  1.06                                              4    3 0  0  --CH.sub.2 --CH.sub.2 --                                                                 80  1.98                                              5    1 18 0  --CH.sub.2 --CH.sub.2 --CH.sub.2 --                                                      80  1.8                                               6    1 1  1  --CH.sub.2 --CH.sub.2 --CH.sub.2 --                                                      80  1.96                                              7    1 2  2  --CH.sub.2 --CH.sub.2 --CH.sub.2 --                                                      80  1.95                                              8    0 18 0  --         80  1.95                                              __________________________________________________________________________     (*) It is recalled that, in the amino compound formula, each of R.sup.1       and R.sup.2 may represent the hydrogen atom or an alkyl radical:              respectively C.sub.n H.sub.2n+1 and C.sub.m H.sub.2m+1 (with each of n an     m ranging from 1 to 24). When R.sup.1 or R.sup.2 represents the hydrogen      atom, the reported value of n or m is 0.                                 

EXAMPLES 9 to 24

Examples 9 to 18 describe the preparation of copolymer compositionsaccording to the invention, using nitrogenous monomers prepared asdescribed in examples 1 to 8, several methacrylates (methyl methacrylate-in short MMA-, lauryl methacrylate- in short LM-, and styrenemethacrylate-, in short SM) and styrene in the proportions by weightindicated in Table 2. In examples 19 to 24, by way of comparison,various copolymers have been prepared without using nitrogenous monomerssuch as those involved in examples 9-18, or by using other nitrogenousmonomers: N-vinylpyrrolidone (in short NVP), N- vinylimidazole (in shortNVI), triallylcyanurate (in short TAC) and various combinations of thesemonomers. The proportions by weight of monomers involved in thesecomparative examples are also indicated in Table 2.

In these examples, "lauryl methacrylate" and "stearyl methacrylate", asused, are alkyl methacrylate cuts, respectively of 8-18 and 14-22 carbonatoms, whose composition by weight is as follows:

Lauryl methacrylate (in short LM)

13% (±2%) of C₈ alkyl methacrylate

16% (±2%) of C₁₀ alkyl methacrylate

29% (±2%) of C₁₂ alkyl methacrylate

21% (±2%) of C₁₄ alkyl methacrylate

14% (±2%) of C₁₆ alkyl methacrylate

7% (±2%) of C₁₈ alkyl methacrylate.

Stearyl methacrylate (in short SM)

2% (±2%) of C₁₄ alkyl methacrylate

51% (±2%) of C₁₆ alkyl methacrylate

30% (±2%) of C₁₈ alkyl methacrylate

14% (±2%) of C₂₀ alkyl methacrylate

3% (±2%) of C₂₂ alkyl methacrylate.

                                      TABLE 2                                     __________________________________________________________________________         nitrogenous     MMA LM  SM  Styrene                                      Example                                                                            monomer         % by                                                                              % by                                                                              % by                                                                              % by                                         N.sub.o                                                                            N.sub.o  % by weight                                                                          weight                                                                            weight                                                                            weight                                                                            weight                                       __________________________________________________________________________    9    1        1      8   59  32  0                                            10   1        1      6   48  20  25                                           11   1        3.7    7   48.3                                                                              21  20                                           12   2        1      8   49  22  20                                           13   3        3.7    6   46.3                                                                              19  25                                           14   4        3.7    7   48.3                                                                              21  20                                           15   5        3.7    7   48.3                                                                              21  20                                           16   6        1      8   49  22  20                                           17   7        3.5    7   48.5                                                                              21  20                                           18   8        3.5    6   46.5                                                                              19  25                                           19*  --       0      8   50  22  20                                           20*  NVP      3.7    7   48.3                                                                              21  20                                            21*  2NVP                                                                                  3.7    7   48.3                                                                              21  20                                                1NVI                                                                     22*  TAC      1.7    8   49  21.3                                                                              20                                           23*  TAC      3.1    7   48.3                                                                              21  20                                           24*  TAC+     3.7    7   47.3                                                                              20  20                                                2NVP/1NVI                                                                __________________________________________________________________________     *comparative examples                                                    

The weight molecular weights of the products range from 200,000 to400,000 (as determined by chromatography by gel permeation calibratedwith methyl polymethacrylate); the polydispersity of products ofexamples 9-18 ranges from 2.7 to 4.7.

Typical conditions for obtaining copolymers as described in examples 9to 19, 22 and 23 are the following:

Into a heating reactor provided with mechanical stirring means, a vacuumport and a circulation of inert gas, are introduced:

    __________________________________________________________________________    Solvent:       100N oil      25% by weight                                                   MMA                                                            Monomers       LM                                                                            SM            74.5% by weight                                                 Styrene (except ex. 9)                                                                      (distribution according                                         nitrogenous comonomer                                                                       to table 2)                                                     (except ex. 19)                                                Radical initiator (benzoyl   0.5% by weight.                                  peroxide)                                                                     __________________________________________________________________________

The reactor is thoroughly degased by subjecting it successively to areduced pressure and to a light pressure of inert gas. The reactor isthen heated to 100° C. for 5 hours under stirring; then the temperatureis increased up to 130° C for 2 hours, so as to complete the initiatordecomposition and to polymerize monomer residues, if any.

The copolymer compositions of comparative examples 20, 21 and 24 areprepared according to an identical operation mode with introduction ofNVI and/or NVP at the end of the polymerization.

EXAMPLE 25 (Determination of the additive properties)

Various properties of the additives, prepared in examples 9 to 18according to the invention and in comparative examples 19 to 24, aredefined as follows:

(a) Thickening power (in short TP) of the additive. It is defined as theamount of additive to dissolve in a 200N oil for reaching the viscosityof 15 mm² /s at 100° C.

(b) Pour point of a 200N oil comprising a proporation of additivedetermined according to (a) and measured according to standard AFNOR T60105.

(c) Shearing strength of 200 N oil comprising the above additiveproportion. It is determined by a test in ORBAHN injector according tostandard DIN 51382 after 30 cycles; it is expressed by the relative lossof kinematic viscosity (-Δη%).

(d) Additive dispersing power. The dispersing efficiency of thecompositions according to the invention is evaluated by the dispersionspot test on filter paper, in the presence of carbonaceous materialoriginating from Diesel engine used oil. The ratio between therespective diameters of the black spot and of the oil aureole isdetermined after 48 hours, the mixture being subjected, beforedeposition on filter paper, to different treatments.

The quotations retained for this test are the following:

    ______________________________________                                         ##STR8##                                                                              quotation          dispersion                                        ______________________________________                                        <32%              0        none                                               32-39%            1        very low                                           40-56%            2        poor                                               57-68%            3        mean                                               68-74%            4        good                                               ≧75%       5        very good                                          ______________________________________                                    

The results of these determinations are indicated in the followingtables 3 and 4.

                  TABLE 3                                                         ______________________________________                                                  TP              Pour                                                Additive of                                                                             %               point  -Δη                                example   by weight       (°C.)                                                                         %                                            ______________________________________                                        9         4.2             -33    30                                           10        4.1             -24    17                                           11        3.7             -27    24                                           12        4.3             -30    18                                           13        3.8             -24    20                                           14        4.7             -27    17                                           15        4.5             -27    17                                           16        4.3             -27    18                                           17        4.1             -27    19                                           18        4.8             -24    15                                           19*       3.05            -30    30                                           20*       3.8             -30    20                                           21*       3.3             -27    24                                           22*       3.7             -30    20                                           23*       3.5             -30    23                                           24*       3.05            -30    25                                           ______________________________________                                         *Comparative examples                                                    

                                      TABLE 4                                     __________________________________________________________________________    Dispersing efficiency                                                         Additive of                                                                         without H.sub.2 O                                                                             with H.sub.2 O                                          example                                                                             20° C.                                                                     200° C./10'                                                                  250° C./10'                                                                  20° C.                                                                     200° C./1'                                                                   200° C./10'                            __________________________________________________________________________    9     4   3     3     4   3     3                                             10    4   3     3     3   4     3                                             11    4   3     3     4   4     4                                             12    4   4     4     4   4     4                                             13    5   5     4     5   5     4                                             14    4   4     4     4   4     4                                             15    4   4     3     4   4     4                                             16    4   4     4     4   4     4                                             17    4   4     4     4   5     4                                             18    4   4     3     4   3     3                                             19*   1   1     1     1   0     1                                             20*   3   2     2     3   3     2                                             21*   3   3     3     3   3     3                                             22*   2   1     1     2   1     1                                             23*   2   1     1     2   1     1                                             24*   3   3     3     3   3     3                                             __________________________________________________________________________     *Comparative examples                                                    

According to Table 4, it appears that, under the test conditionsselected and for the indicated distributions of methacrylic and styrenicrecurrent units, the incorporation of nitrogenous monomers with thepreparation of the copolymers according to the invention gives gooddispersing properties to the resultant additives.

Example 19 shows that the copolymer prepared in the absence ofnitrogenous monomer has but a very low dispersing efficiency. Examples20 and 21 relate to copolymers grafted according to conventionaltechniques with the usual NVP and NVI monomers.

Examples 22 and 23 show the very low efficiency of triallylcyanuratewhen incorporated as such with the additive.

Example 24 relates to a copolymer prepared by grafting a mixture of 2/3NVP and 1/3 NVI on a copolymer such as that of example 23. The previousincorporation of TAC does not improve the dispersing efficiency obtainedby introduction of the mixture of NVP and NVI at the end of thepolymerization (compare with example 21).

Examples 9 to 18 relate to copolymers according to the invention andillustrate the variety of possible structures of nitrogenous monomercharacterizing the invention and of copolymer compositions including it.

EXAMPLE 26

In order to ascertain that the dispersing efficiency depends effectivelyon the nitrogenous groups fixed on the polymer, the products of examples11, 15 and 16 have been treated by dialysis for removing the monomerswhich were not copolymerized or the polymers of low molecular weight.

The dialysis is performed by using as the solvent, cyclohexane atreflux. After separation, the polymer fraction is precipitated intomethanol, dried and again dissolved into 200N oil.

After dialysis, it appears that the polymer of high molecular weightamounts to more than 95% by weight of the monomers initially introducedand that the dispersing efficiency of the polymer after dialysis isidentical to that of the initial polymer solution.

What is claimed as the invention is:
 1. A copolymer composition,comprising (a) 55-99.8% b.w. of recurrent units derived from at leastone acrylic or methacrylic ester and (b) 0.2-10% b.w. of recurrent unitsderived from at least one nitrogenous vinyl monomer obtained by reactingtriallylcyanurate with at least one monoprimary or biprimary aliphaticamine, complying with the general formula: ##STR9## wherein R¹ is ahydrogen atom or an alkyl radical --C_(n) H_(2n+1), in which n is aninteger from 1 to 24, x ranges from 1 to 10 or may be a 0 when n is atleast 4, R² is a hydrogen atom or an alkyl radical --C_(m) H_(2m+1), mbeing an integer from 1 to 24, and A is an alkylene group of 2-6 carbonatoms, said nitrogenous vinyl monomer containing 1 or 2 triazine ringsand comprising at least one allyl group.
 2. A copolymer according toclaim 1, further comprising (c) not more than 35% b.w. of recurrentunits derived from at least one vinyl-aromatic monomer.
 3. A copolymercomposition according to claim 2, wherein said vinylaromatic monomer isstyrene.
 4. A copolymer composition according to claim 1, wherein saidacrylic or methacrylic ester consists of at least one linear or branchedalkyl acrylate or methacrylate having 1 to 22 carbon atoms in the alkylgroup.
 5. A copolymer composition according to claim 1, having a weightaverage molecular weight from about 200,000-400,000 and a polydispersityof 2.7-4.7.
 6. A copolymer composition according to claim 1, having aweight average molecular weight from about 30,000 to 800,000 and apolydispersity lower than
 5. 7. A copolymer composition according toclaim 1, wherein said nitrogenous vinyl monomer results from thereaction of about 1 to 2 moles of monoprimary or biprimary amine permole of triallylcyanurate, with removal of the allyl alcohol formed. 8.A copolymer composition according to claim 1, wherein said nitrogenousvinyl monomer results from the reaction of about 0.5 mole of biprimaryamine per mole of triallylcyanurate, with removal of the allyl alcoholformed.
 9. A copolymer composition according to claim 1, wherein theamine is N-octadecyl propane diamine.
 10. A copolymer compositionaccording to claim 9, wherein the amine is N-octadecyl propane diamine.11. A copolymer composition according to claim 3, wherein said acrylicor methacrylic ester consists of at least one linear or branched alkylacrylate or methacrylate having 1 to 22 carbon atoms in the alkyl group.12. A copolymer composition according to claim 11, having a weightaverage molecular weight from about 30,000 to 800,000 and apolydispersity lower than
 5. 13. A copolymer composition according toclaim 12, wherein the nitrogenous vinyl monomer is obtained by reacting1-2 moles of the monoprimary of biprimary amine with one mole ortriallylcyanurate.
 14. A copolymer composition according to claim 12,wherein said nitrogenous vinyl monomer is obtained by reactingtriallylcyanurate with at least one monoprimary aliphatic amine.
 15. Acopolymer composition according to claim 12, wherein said nitrogenousvinyl monomer is obtained by reacting triallylcyanurate with at leastone biprimary aliphatic amine.
 16. A copolymer composition according toclaim 15, wherein said monoprimary aliphatic amine is n-butylamine,sec-butylamine, tert-butylamine, n-pentylamine, 4, 3 or 2methyl-n-butylamine, n-hexylamine, n-heptylamine, n-octylamine,n-nonylamine, eicosylamine, docosylamine, N,N-dimethyl ethylenediamine,N-oleyl propane diamine, N,N-dimethyl diamino-propane, or N,N-diethyldiamino-isopropane.
 17. A copolymer composition according to claim 16,wherein the biprimary aliphatic amine is ethylene diamine, propylenediamine, diethylene triamine, dipropylene triamine, triethylenetetramine, tripropylene tetramine, tetraethylene pentamine, ortetrapropylene pentamine.
 18. A copolymer comprising:(a) 55 to 99.8% byweight of least one linear or branched alkyl acrylate or methylacrylatehaving 1-22 carbon atoms in the alkyl group; (b) 0.2-10% by weight of##STR10## wherein R¹ is a hydrogen atom or an alkyl radical --C_(n)H_(2n+1), in which n is an integer from 1 to 24, x ranges from 1 to 10or may be a 0 when n is at least 4, R² is a hydrogen atom or an alkylradical --C_(m) H_(2m+1), m being an integer from 1 to 24, and A is analkylene group of 2-6 carbon atoms, and R³ represents CH₂ ═CH--CH₂ --;and (c) 0-35% by weight of a vinyl aromatic monomer.
 19. A copolymercomposition according to claim 18, wherein said the monomer (b) ispresent in a concentration of 0.5-4% by weight and said vinyl aromaticmonomer is styrene in a proportion of above 0% by weight.